Dr. Michael Ciccotti: Investigating ACL Injuries in Female Athletes

March 27, 2000

Dr. Michael Ciccotti: Investigating ACL Injuries in Female Athletes

By Janelle Mallett, Knee1/Body1 Staff

Over the past decade the University of Tennessee’s Women’s Basketball Team has averaged almost one ACL tear per year. Not necessarily an alarming statistic, until you consider that the men’s team reported no ACL tears during the same period. The predominance of ACL injuries in female athletes has become one of the most controversial topics in sports medicine today. Researchers and clinicians have been studying the problem for solutions on how to lower that risk and improve the quality of participation in sports for all female athletes, whether amateurs or professionals. One physician at the forefront of such research is sports medicine specialist Dr. Michael Ciccotti of the Rothman Institute at Thomas Jefferson in Philadelphia.

Dr. Ciccotti graduated from the College of the Holy Cross in Worcester, M.A. with a B.S. in Biology before receiving his M.D. from Georgetown University School of Medicine in Washington D.C. in 1986. After 5 years of post-graduate medical training in orthopedics at Thomas Jefferson University Hospital (TJUH) in Philadelphia, Dr. Ciccotti gained expertise at the Los Angeles Kerlan-Jobe Orthopaedic Clinic, one of the premier sports medicine clinics in the world, working with sports medicine specialist and pioneer Dr. Frank Jobe. While there, he served as a team physician assistant for a number of Los Angeles professional sports teams, including the Lakers, Dodgers, Rams, and Kings, as well as the Professional Golf Association and the Professional Tennis Association and the University of Southern California. He then returned to the Rothman Institute at TJUH where began his academic and clinical career in sports medicine.

In addition to maintaining his clinical practice, Dr. Ciccotti also serves as an Associate Professor of Orthopedic Surgery, Chief of the Division of Sports Medicine, Program Director for the Sports Medicine Fellowship and Co-Director of the Orthopedic Residency at Rothman Institute and TJUH. He has served as orthopedic consultant for the U.S. Women’s National Soccer Team and the Philadelphia Flyers Hockey Team. He currently is the Team Physician for the Philadelphia Phillies Baseball Team as well as for St. Joseph’s University. He has been named as one of the Top Doctors in Philadelphia as well as one of the Best Doctors in America.

Knee1: Do you notice correlations between the types of sports played and the injuries developed by active athletes?

Dr. Ciccotti: Yes, we can certainly generalize about certain groups of injuries. The throwing sports like baseball have primarily upper extremity injuries, like those in the shoulder. The running sports may have lower extremity injuries such as involving the ankles. The contact running sports like football and soccer have a high incidence of knee injuries.

Knee1: Are you then able to warn your patients against certain types of injuries or teach them proper training techniques?

Dr. Ciccotti: That is really one of the wonderful aspects of orthopedic sports medicine. Not in all cases can we prevent these injuries. But in many instances, we can develop training techniques that will potentially limit further injuries from occurring.

Knee1: As I understand, there is a higher incidence of ACL injuries in female athletes as compared to males in all sports.

Dr. Ciccotti: Yes, that’s now one of the hottest topics in sports medicine: ACL injuries in female athletes. Certainly the letters A-C-L strike fear in the hearts of countless female athletes who have heard many horror stories of such injuries. Over the past several decades, female participation in sports at all levels has increased dramatically, allowing medical researchers to more precisely define the female athlete in terms of her training, ability, injury patterns and healing response. The NCAA conducted a five-year study from 1989 through 1993 revealing women are 4 times more likely to tear their ACL than men are. A follow-up study from 1994 to 1998 confirmed those findings. There are many specific examples in women’s sports, like the NY Liberty’s Rebecca Lobo, who tore her ACL last June at the start of the season. She went through a successful surgery and rehabilitation. Then in December she tore it again. The University of Tennessee women’s basketball team has had one of the most storied programs in the history of women’s college basketball. Over the last 13 years, they have averaged at least one ACL tear per year, whereas the men’s basketball team at the University of Tennessee has gone without one tear in the same time period. The obvious question to researchers is why does that happen? It seems like the problem is multifactorial.

Knee1: How does one advance from recognition of a problem to identifying particular factors such as hormones, morphometric factors and training techniques that could lead to injury?

Dr. Ciccotti: Well you begin by identifying the problem: the gender disparity in ACL injury rates. And then you look at the subjects, male and female athletes in the same sports at the same level of competition. You then try to define the differences that exist between them. There are certain skeletal differences that we have identified. The female pelvis is generally wider than the male pelvis which may result in an increased inward angulations, or valgus alignment, at the knee joint. The ACL may be smaller in the female athlete and the space within which the ACL lies in the knee may be narrower in females. We’re currently evaluating female and male athletes with magnetic resonance imaging (MRI) to precisely define the size and shape of the ACL and the dimensions of the bony space within which it lies. These bony factors may predispose the female athlete to this dreaded injury.

We all know that women and men have different hormonal patterns. During pregnancy and certainly at the time of birth, the female body has increased levels of certain hormones like estrogen and relaxin that soften and relax the ligamentous structure of the pelvis region so the baby can be born. It has been postulated, then, that even during the normal female monthly cycle, as estrogen levels fluctuate, they may “soften” ligaments including the ACL and predispose it to injury. We’ve recently completed a study here at the Rothman Institute that has looked at the effects of fluctuating estrogen levels of knee ligament stability. We evaluated healthy women without any history of prior knee injuries who were in their third trimester of pregnancy when estrogen levels are known to be extremely high. We confirmed the high levels of estrogen in their blood streams with blood testing and we measured the laxity of their ACL’s with a knee ligament-testing device. Six weeks postpartum, when estrogen levels are back to normal, we re-examined these women by confirming their lower estrogen levels with blood testing and then retesting their knee ACL laxity. We documented that their knees were significantly tighter in the postpartum period when their estrogen levels were down. This study suggests that estrogen may be related to ligament injuries.

We also know that there are certain thigh muscular differences that exist between males and females. Males have a roughly equal ratio of quadriceps strength and hamstring strength, whereas females have far less hamstring strength than quadriceps strength. The hamstrings actually protect the ACL by holding the lower leg in a protective position. If females have less hamstring to quadriceps strength, then that may predispose them to ACL injury. We are currently looking at specific training programs to improve that hamstring strength and hopefully safeguard against ACL tears.

Finally, we know that there are certain differences in technique between male and female athletes. When pivoting, women athletes in general have increased internal rotation of the lower leg and that may put increased force on the ACL. We are attempting to modify those technique differences by instructing female athletes on the way they play their sport. And so we see that this problem is multi-factorial. Some of these factors such as the body and hormonal differences are as of yet unalterable, but other factors such as the muscular and technique differences may be altered to reduce ACL injuries in women. We will have to watch the levels of ACL injuries in female athletes and monitor the effectiveness of our efforts when working with female athletes.

Knee1: We have talked about your research on the ACL, but tell me more about your work on cartilage injury and repair.

Dr. Ciccotti: Up until approximately 5 to 7 years ago when a healthy, athletically active person, injured the articular surface of the knee joint, or chipped off a portion of articular cartilage, there was very little that could be done to get that athlete back reliably to his or her sport. The surgical techniques that were adopted could not restore a normal surface to the articular cartilage. The theory behind Carticel is that a small sample of normal cartilage is harvested arthroscopically and then sent to the lab where, under sterile conditions, the cartilage cells are cultured and expanded. In a second phase procedure a fibrous membrane is sutured over the injury site. Then the cultured cartilage cells are injected almost like a soup underneath the fibrous membrane. In the ensuing months, those cartilage cells grow into the type of hyaline cartilage that sits on the end of our bones and joints, generating a smooth surface.

Carticel, the company that has developed this procedure, is making great efforts to collect data to substantiate this elaborate technique. Carticel’s data registry, which has been accumulating the results of this procedure worldwide, indicates that, depending on the particular area of the injury, this technique may return athletes to their pre-injury level of activity upwards of 85-90%; something that we could not previously promise these athletes.

Knee1: Are there continuing efforts to improve this cartilage repair technique?

Dr. Ciccotti: Yes. The Carticel implantation really involves two procedures that we are trying to perfect. The first is arthroscopic: identifying the damaged region and taking a small sample of cells. We are currently trying to improve our ability to precisely size the injured area and safely obtain the cartilage sample. The second phase of the technique involves a standard incision to reimplant those cells. The technique of placing that fibrous membrane over the defect site and meticulously suturing that membrane necessitates the open incision. The goal is to be able to ultimately perform this second phase arthroscopically. This requires development of instrumentation and surgical techniques. And as we achieve these goals, this will decrease the risks, shorten the recovery, and improve the outcome of this existing technology.

Knee1: Well, we’ve discussed some truly exciting sports medicine research that you are involved in, but how does the scientist bring such research endeavors to the patient level?

Dr. Ciccotti: The topics that we’ve discussed on the ACL and cartilage repair are but two areas in the tremendously exciting realm of orthopedic sports medicine research. And yet our patients perception of how these treatments improve their lives is the ultimate benchmark. Outcome studies are our way of doing just that. These are specific questionnaires that our patients fill out to define their perception of how our surgical and non-surgical treatment has improved their lives, including during athletic activities, sleep and other daily actions. We have refined our sports knee outcome tool and are extrapolating it to include sports shoulder, elbow and ankle so that we can precisely assess the impact of our research and development in the orthopedic and sports medicine fields. In doing so, we will be better able to treat our patients inquiries and hopefully someday prevent them from occurring.

Knee1: In addition to your busy clinical practice, you are involved in a variety of research programs. Tell me about the sports research activities at TJUH.

Dr. Ciccotti: At TJUH, we have one of the highest NIH (National Institute of Health) funded orthopedic labs in the country. Our faculty is involved in as much, if not more, orthopedic research as any other orthopedic faculty in the United States. We have three main lab sites staffed by over 100 people, 12 of them full-time research and teaching faculty. Dr. Rocky Tuan, who is vice-chairman of the orthopedic department at TJUH, directs our main lab. This lab focuses on the basic science of cartilage injury and treatment including tissue culture, biochemistry and gene therapy. More specifically, we are involved in the evaluation of hormonal influences on ligaments such as the ACL, the biology of healing of the graft tissues we use for ACL reconstruction and the science of cartilage cell expansion and delivery for injured joint cartilage.

A second lab is devoted to motion analysis of not only sports, but also activities of daily life. This includes the use of electromyography (EMG), force plate and vicon analysis to study the motion of normal, injured and rehabilitated joints. More specifically, we are developing a more precise diagnostic assessment of ACL injuries; training techniques for ACL injured athletes and hopefully measures to prevent these injuries from occurring.

The third lab is focused on biochemical testing of the surgical devices and techniques we use. We are evaluating the biomechanical properties of normal ligaments, injured ligaments, repaired ligaments and reconstructed ligaments. Also, we are evaluating the strengths and fatigue properties of the implants we use in sports surgery.

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